757
FXUS65 KBYZ 221906
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
106 PM MDT THU OCT 22 2026
KEY MESSAGES
- STORM SYSTEM LATE TONIGHT INTO SATURDAY MORNING BRINGS LOWER
ELEVATION RAIN AND MOUNTAIN/HIGHER FOOTHILLS SNOW; GREATEST
PRECIPITATION TOTALS EXPECTED WEST OF BILLINGS, WITH LITTLE TO
NO PRECIPITATION OVER SE MONTANA.
- CRITICAL FIRE WEATHER CONDITIONS FRIDAY AFTERNOON/EVENING FROM
SHERIDAN COUNTY EASTWARD ACROSS MUCH OF SE MONTANA.
- WINDY CONDITIONS (GUSTS 25-45 MPH) EXPECTED FRIDAY INTO SATURDAY
MORNING.
- SEASONAL TEMPERATURES (HIGHS IN THE 50S) AND UNSETTLED
CONDITIONS (20-40% PRECIPITATION CHANCES) SUNDAY THROUGH
WEDNESDAY. UNCERTAINTY IS HIGH FOR THE EXTENDED FORECAST.
DISCUSSION
REST OF TODAY THROUGH WEDNESDAY...
WARM AND DRY CONDITIONS THIS AFTERNOON WITH PERIODS OF CLOUDS
PUSHING THROUGH FROM SOUTHWEST TO NORTHEAST. AFTERNOON
TEMPERATURES WILL BE WELL INTO THE MID 70S WITH A FEW LOCATIONS
CLOSE TO 80 DEGREES BY 4PM.
STORM SYSTEM LATE TONIGHT THROUGH SATURDAY MORNING...CHANGES FROM
THE RECENT WARM AND DRY PATTERN BEGIN LATE TONIGHT AS AN UPPER
LEVEL LOW OVER THE GREAT BASIN PUSHES THIS DIRECTION THROWING
INCREASED MOISTURE OVER THE AREA, AND A CANADIAN TROF SLIDES IN
FROM THE NORTHWEST BRINGING COLDER AIR AND ADDITIONAL UPPER LEVEL
SUPPORT FOR PRECIPITATION. THE GOOD NEWS IS MODELS HAVE
CONSOLIDATED THEIR THINKING OVER THE PAST 24 HOURS AND THE
FORECAST HAS STABILIZED, SO NO BIG CHANGES WITH THIS FORECAST
PACKAGE.
EXPECT SHOWERS, AND POSSIBLY AN ISOLATED THUNDERSTORM, TO BUILD
INTO SOUTHWEST MOUNTAIN/FOOTHILLS ZONES OVERNIGHT AND INTO THE
SUNRISE PERIOD. MAIN FRONT WILL PUSH INTO NORTHWEST ZONES AROUND
NOON WITH A GOOD DEAL OF WIND (GUSTS 30-45 MPH WITH A FEW LOWER
50S HERE AND THERE) BEHIND IT THANKS TO 2-3MB/HR PRESSURE RISES
BEHIND THE FRONT. THE STRONGEST WINDS ARE EXPECTED FROM MID
AFTERNOON THROUGH LATE FRIDAY NIGHT. PRECIPITATION WILL FILL IN
ALONG AND BEHIND THE FRONT WITH HIGH CHANCES FOR THE WESTERN 2/3
OF THE AREA THROUGH FRIDAY EVENING. EASTERN ZONES STILL LOOK TO
GET LEFT OUT OF SIGNIFICANT PRECIPITATION WITH THIS SYSTEM, BUT
THERE IS STILL A 15-30% CHANCE FOR A SHOWER/THUNDERSTORM LATE
AFTERNOON INTO THE EVENING HOURS. OVERALL, THE BULK OF
PRECIPITATION WILL BE DONE BY MIDNIGHT FRIDAY NIGHT WITH CHANCES
DIMINISHING THROUGH SUNRISE AS THE UPPER LEVEL ENERGY SPLITS NORTH
AND SOUTH OF THE AREA LEAVING JUST SOME LINGERING GUSTY WINDS AND
MUCH COOLER TEMPERATURES FOR SATURDAY.
RAINFALL FORECAST SHOWS THE PROBABILITY FOR A QUARTER INCH OR MORE
IN THE 30 TO 50 PERCENT RANGE WEST OF A ROUNDUP TO HARDIN LINE,
WITH 60-100 PERCENT WEST OF A RYEGATE TO BIG TIMBER LINE AND INTO
THE WESTERN MOUNTAINS. FROM ROSEBUD COUNTY EAST THE PROBABILITIES
FOR A TENTH OF AN INCH OF PRECIPITATION ARE UNDER 20 PERCENT, AND
NEAR ZERO FOR MOST OF CARTER AND FALLON COUNTIES.
NO SIGNIFICANT CHANGES TO THE SNOWFALL FORECAST THIS AFTERNOON.
STILL LOOKING AT A DUSTING IN THE WESTERN FOOTHILLS WITH 4 TO 8
INCHES IN THE BEARTOOTH/ABSAROKA/CRAZY MOUNTAINS, AND 4 INCHES OR
LESS FOR THE BIGHORN AND PRYOR MOUNTAINS. SNOW LEVELS FALL TO
UNDER 4KFT AFTER 3AM FRIDAY NIGHT, SO THERE COULD BE A FEW FLAKES
MIXED IN ACROSS THE LOWER ELEVATIONS DOWN TO 3200FT AS
PRECIPITATION IS TAPERING OFF EARLY SATURDAY MORNING, BUT DO NOT
EXPECT ANY IMPACTFUL SNOWFALL (>1 IN) OUTSIDE OF THE WESTERN
FOOTHILLS ABOVE AROUND 5KFT.
WILL ISSUE A WINTER WEATHER ADVISORY FOR THE JUDITH GAP ZONE FOR
LATE FRIDAY AFTERNOON THROUGH 6AM SATURDAY. STRONG NORTHERLY WINDS
WILL COMBINE WITH SNOWFALL THERE (2 INCHES OR LESS) TO MAKE
TRAVEL DIFFICULT ALONG US-191 FROM HARLOWTON UP THROUGH JUDITH
GAP. HEAVIEST SNOW WILL BE IN THE 8PM THROUGH 2AM RANGE AND WIND
GUSTS 40-55 MPH WILL CREATE POOR VISIBILITY IN BLOWING SNOW. ROADS
WILL BE MAINLY SLUSHY OVERNIGHT, BUT SOME SLICK SNOW COVERED SPOTS
CAN BE EXPECTED ESPECIALLY OVER THE HIGHER HILLS ALONG THIS ROUTE.
FIRE WEATHER...AHEAD OF THE FRONT OVER NC WY/SE MT SOUTH-
SOUTHWEST WINDS GUSTING 30 TO 40 MPH WILL DEVELOP AND PERSIST
UNTIL THE FRONT ARRIVES EARLY EVENING. POST FRONTAL WINDS WILL
SHIFT TO THE NORTHWEST WITH GUSTS TO 45 MPH THROUGH THE EARLY
MORNING HOURS. AFTERNOON TEMPERATURES IN THIS AREA WILL RANGE FROM
75 TO 85 DEGREES (20-30 DEGREES ABOVE NORMAL), IN THE RECORD HIGH
TEMPERATURE RANGE FOR THE DAY. RH VALUES WILL DROP INTO THE
15-25% RANGE AS WELL. SO, THIS SETS UP AS A CRITICAL WEATHER
SCENARIO FOR GRASS FIRE DANGER FROM SHERIDAN COUNTY EAST ALONG THE
MT/WY STATE LINE. WILL ISSUE A RED FLAG WARNING FOR FRIDAY
AFTERNOON THROUGH 9PM FRIDAY EVENING FOR THE SHERIDAN FOOTHILLS
AND A GOOD PORTION OF SE MONTANA TO COVER THIS SCENARIO.
STORM SYSTEM DISSIPATES SATURDAY AFTERNOON FOR A SEASONALLY COOL
AND BREEZY AFTERNOON.
THE NEXT CONCERN IS ANOTHER UPPER LOW MOVING NORTHEAST FROM THE
GREAT BASIN AND CLIPPING SE MONTANA LATE SUNDAY INTO MONDAY.
MODELS ARE STEADILY RAMPING UP PRECIPITATION CHANCES (20-40%) FOR
THIS AREA. RIGHT ON THE HEALS OF THE GREAT BASIN SYSTEM, A
STRONGER AND MORE ORGANIZED PACIFIC SYSTEM PUSHES INTO THE AREA
FROM THE WEST FOR TUESDAY AND WEDNESDAY WITH MORE WIDESPREAD
30-50% PRECIPITATION CHANCES. LATES MODEL RUNS ARE TAPPING SOME
COLDER AIR WITH THIS SYSTEM BY WEDNESDAY ALONG WITH BETTER UPSLOPE
FLOW INTO NORTH FACING MOUNTAINS/FOOTHILLS THAN PREVIOUSLY
ADVERTISED, SO PRECIPITATION CHANCES COULD CONTINUE TO RISE WITH
THIS SYSTEM GOING FORWARD, AND MAY SEE CHANCES FOR LOWER ELEVATION
SNOWFALL MIX IN TOO. AS MENTIONED YESTERDAY THERE IS STILL
CONSIDERABLE UNCERTAINTY WITH THE FORECAST FOR NEXT WEEK SO STAY
TUNED TO THE FORECAST AS DETAILS GET IRONED OUT GOING FORWARD.
CHAMBERS
AVIATION
RAIN/SNOW SHOWERS ARE EXPECTED TO MOVE INTO THE REGION AROUND
12-15Z FRIDAY WITH SNOW LEVELS AROUND 9,000 FT, DROPPING TO 6,000
FT IN THE EVENING. BREEZY PREFRONTAL WINDS ARE FORECAST TO BEGIN
LATE MORNING ACROSS NORTHERN WY AND SOUTHEAST MT. MOUNTAIN WAVE
ACTIVITY IS POSSIBLE ACROSS THE BIGHORN FOOTHILLS WHICH COULD LEAD
TO PERIODIC GUSTY AND ERRATIC WINDS AT KSHR MID DAY FRIDAY. GUSTY
FRONTAL WINDS 30-45KTS, BECOMING WEST TO NORTHWEST, ARE EXPECTED
ACROSS THE REGION BEGINNING LATE MORNING, LASTING WELL INTO THE
EVENING. MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH THE DAY
FRIDAY. TS
PRELIMINARY POINT TEMP/POPS
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 051/069 035/050 031/051 031/051 033/053 034/049 031/049
06/R 80/U 00/U 00/B 12/W 32/W 11/B
LVM 046/058 024/047 023/050 025/052 027/054 027/049 025/051
09/R 90/U 00/U 00/B 24/W 42/J 11/B
HDN 050/074 030/053 025/055 028/055 030/055 029/050 025/052
16/R 90/U 00/U 01/B 13/W 32/W 11/B
MLS 050/076 035/048 029/053 032/050 032/052 031/046 028/049
02/R 60/U 00/U 11/B 11/B 32/W 10/B
4BQ 053/081 035/048 031/051 033/050 034/056 034/048 030/052
02/R 30/U 01/B 11/B 12/W 31/U 10/B
BHK 051/083 030/047 024/050 026/046 026/051 027/046 024/049
01/N 20/N 00/U 22/W 21/B 32/W 10/B
SHR 050/077 027/050 025/053 027/055 030/057 029/052 026/054
02/R 40/U 01/U 11/U 12/W 31/U 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM FRIDAY TO 6 AM
MDT SATURDAY FOR ZONE 63.
RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT FRIDAY FOR
ZONES 131-133.
WY...RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT FRIDAY FOR
ZONE 274.
WEATHER.GOV/BILLINGS
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